Friday, August 31, 2018

Update - 08/31/18

There is currently a LOT of tropical activity across the Pacific Ocean (entire basin) that shows no sign of letting up.  The Atlantic may have a period too of increased activity, at least for the first half of September.  Will any of this have an impact on the high plains?  It should, at least indirectly.

In the previous post I did on the 22nd (you can read that by clicking here) I was expecting the "gravy train" of widespread rainfall across the high plains to come to an end, at least temporarily and also to heat up.  After the abnormally cool period, temperatures did warm up significantly with several days of readings around 100 at spots.  Rainfall did occur but more scattered across the high plains.  It's interesting that the wettest area of western Kansas so far this year also got the majority of the latest heavy rainfall!   Here is the 7 day accumulation...

Some areas got pounded again with heavy rain but the areal coverage was small.  Much of the region got nothing at all or very little.  Here is the latest drought map that was generated earlier in the week (doesn't take into account late week rains across Iowa)...

Looking at this mornings satellite image....

There were two tropical systems moving towards Hawaii, again.  But just lake Hurricane Lane, they will encounter cooler water and should start to drift north or get shredded by winds aloft.  I don't see much impact to the U.S. mainland, at least at this point.  I will point out, however, that before Fall concludes there could be a threat to southern California.  It has happened before but it would be a rare occurrence.

More importantly is that red X (upper level disturbance) north of Reno Nevada.  It is headed southeast and will move across the plains later in the weekend.  That will combine with an increasing moist tropical fetch of moisture coming up from the Gulf of California.  The result will be several rounds of thunderstorms with excessive rainfall a possibility.  After that goes by there may continue to be a tropical fetch so additional chances will exist through that first full week of September.  For those with interests for the midwest/corn belt, the rainfall will likely be extreme producing widespread flooding!

Here is the outlook from the Weather Prediction Center through the end of next week.  Keep in mid that this is more of an average - some areas will get less, some more.  Also, at the time of this posting their latest outlook wasn't available.  I feel rains across western Kansas may be UNDER estimated in this outlook particular outlook. 

I'm still evaluating expected conditions for the remainder of September.  This upcoming wet period really wasn't showing itself a week ago.  IF the projected precipitation outlook verifies, that would have an impact going well into September as temperatures would be moderated from wet soils and also a continued "green" landscape.  I'll try and update next week.

Wednesday, August 22, 2018

Update - August 22, 2018

This post will have to be somewhat brief as my personal time has been limited lately....

Is the gravy train of rainfall about to come to an end, again?  Recently there has been enough flow aloft to carry thunderstorm clusters off the higher terrain into the western high plains.  Many areas of the high plains have benefited with substantial rainfall but unfortunately some areas with TOO MUCH rainfall!  Also, there were a few severe storms producing very large hail (over 3 inch diameter) but from accounts I found the larger stones were few and far between.  The torrential rain may have been detrimental at some locations.

Over the past 2 weeks, here is an estimate of rainfall across the plains....

As mentioned at the start, some locations had too much rain!  There have been a couple of systems that brought 4 to 6 inches on several occasions.  But, there were also locations that didn't receive that much during this 14 day period, especially across northwest Kansas and far SW Kansas and parts of the panhandles.

The current system (Wednesday/Wednesday night) will bring more thunderstorms but not all areas will benefit.  After this goes by, there will be a drying trend AND warming trend!  Temperatures by the end of the week and through the weekend will be back to normal.

Here was the latest satellite image....

The system (the red L) across Idaho will weaken as it moves into the northern plains.  More importantly is the fetch of tropical moisture from the tropical eastern Pacific ocean that stretches into the inter-mountain west that will likely get cut off for a while, at least into the central plains.  Here is the outlook from the Weather Prediction Center through next Wednesday the 29th....

There may still be scattered thunderstorms during the end of the current week and into next week, but the coverage will be limited even though temperatures will be heating up.

As we get into September, it is one of the most difficult months to forecast for as far as a long range forecast.  The pattern that gets established during the fall (usually late September and early October) will continue in some similar fashion into the following spring and summer and dies out during the following September.  The current pattern of circulation across the globe that got it's start last fall, is waning.  I believe the pattern is starting to transition into the "new" circulation (part old, part new).

Currently what will throw a monkey wrench into the flow aloft is all the typhoon activity across the western Pacific that has been going on for well over a week and now the eastern Pacific tropical activity, i.e., Hurricane Lane and potentially additional tropical activity developing.  I'll have to watch this and give an update on what to expect as we transition into September.  Will it be hot and dry in September?  Possibly but confidence is low.  I'll try and update later next week and give more insight into September and beyond.

Friday, August 10, 2018

Update - 08/10/2018

In the previous post on July 30th, (read that by clicking here) I discussed coming out of the very wet period across the high plains, especially for eastern Colorado and western Kansas.  I suspected that things would dry out considerably through mid-month except for the far western high plains that would still be under the influence of the North American Monsoon.  Looking at the precipitation for this past 7 days it's pretty obvious that it did NOT dry out that much.  Well, except for my hacienda which is smack dab in the middle of the driest part of SW KS!  You would think I would have more control than that! :-)

With the latest episodes of precipitation, there continues to be a bit more improvement on the long term drought conditions across much of the high plains.  The Flint Hills region continues to suffer.

Looking at this afternoons satellite's busy!

The upper high across the Rockies has become very strong and has shut off most of the North American Monsoon, or at least tempered it a little.  There was also a very vigorous upper low approaching the far Pacific Northwest.  There may be some wave energy propagation going on based on what is expected with the little itty bitty X over northeast Kansas.  That feature is expected to move south during the weekend and will interact with lots of thunderstorms developing across north and west Texas.  If all things work out, that little system should gain strength as the result of a lot of latent heat release from the storms.  It appears almost certain that this will occur.  However, what happens next is in question.

Since the steering flow aloft is chaotic and very weak, the movement of that eventual system is very much uncertain.  It "should" drift north late Sunday into mid-week next week.  It will likely move randomly as addition thunderstorms develop every day.  Where it ends up will determine eventual amounts of rainfalls and location of the heaviest.  The margin of error will be huge!  Here is the outlook from the Weather Prediction Center for the next 7 days with the majority of what you see across Kansas and Oklahoma falling by mid week.

Don't count on specific values at this point but the message is clear - there should be a really good chance for beneficial rains across southern Kansas into Oklahoma and central Texas. It "could" be a little farther north and west - it just depends on that eventual track.  Which means?  Yes, it "could" be farther south and east and much of the high plains gets nothing.  Bottom line - check with local forecasts for your area (preferably the NWS).

I did a presentation yesterday at the Kansas Grazing Lands Coalition Range School and one of the things I discussed was the Madden Julian Oscillation.  An outlook or prediction I can make going into September is based off of the MJO.  The following graph shows where the MJO has been and what is expected moving forward.

The current MJO, which was unseasonably strong for a July event, is currently decaying rapidly as it quickly moves into the southern Hemisphere.  The remnants may regenerate across Africa and the western Hemisphere by the last week of August. The prediction is rather convincing for this to happen, at least it should form into another MJO event, just maybe not that strong.   The impacts on the United States often mirrors what has happened during past events.  A composite of MJO sensible weather that occurred in the past during August/September can be seen on the following charts - first for temperatures...

and for precipitation....

The charts increase confidence that the northern plains will be heating up and remaining mostly dry for probably the balance of August.  For the high plains, this increases confidence that temperatures should remain around to perhaps below normal going into the last of August.  As far as precipitation, the end of August into the first week of September may see increased odds for additional rainfall.  Confidence is not extremely high, I would just be leaning in that direction.   Of course, this all hinges on IF the MJO can get going again and there is not other atmosphere forcings that counter the MJO.

More on this in the next post which I hope to do later next week.